Mechanism for removing curling in blanks



P 1935- E. H. BRUNNER El AL 2,012,953

MECHANISM FOR REMOVING CURLING IN BLANKS Filed Jan. 27, 1932 2Sheets-Sheet 1 V lv 67 MI I"! I f I 1 1,59. I I will 14 i L N 6 1 I s e5 I. 46 2 5 S INVENTORS fi I BY 4% want" ATTORNEY.

Patented Sept. 3, 1935 UNITED STATES PATENT OFFICE MECHANISM FORREMOVING CURLING IN BLANKS Ohio Application January 27, 1932, Serial No.589,232

Claims.

This invention relates to a mechanism for operating on blanks formed ofcellulose materials to remove therefrom curling or the natural or normaltendency of the blanks to curl, due to 5 one or more of the followingreasons, to wit,

dampness, atmospheric conditions, surface coatings, difl'erences in rateof contraction of the blanks and coatings or treatment of the blanks forany purpose, whereby the blanks may be laid on a supporting surface,readily handled, stacked, wrapped or stored. The mechanism hereindisclosed has been advantageously used for removing the curl inphotographic prints, after the same have been developed and dried. Theoperations involve reversely curling each blank, that is, subjecting itto folding or rolling passes curved oppositely to its normal curlingtendency, so that the resultant stresses of or in the materialsconstituting each blank will be equalized and thus permit it to liesubstantially flat. The operation involved may be referred to asstraightening or flattening, but in the practical operation of themechanism, the blanks are or may be delivered from the mechanism in theslightly reversed curled condition, so that when they are laid on a flatsurface, stacked or wrapped they will assume a permanent substantiallyflat condition. One object of the invention is to provide a mechanism ofthis type in which the blanks may be subjected to a plurality of passesto curl them reversely to the direction of their normal curl, wherebyany tendency of the material or influence therein by reason ofatmospheric conditions, prior treatment or surface coatings to curl, iseliminated.

Another object of the invention is to provide a mechanism of this typehaving a plurality of successive passes in which the blank is flexed or.curled in opposite directions alternately, the terminal or flnal passserving to curl the blank reversely to its original normal curlingtendency, whereby unequal tension of the fibers of the blank and surfacecoatings thereon are broken down or eliminated.

Another object of the invention is to provide means for reducing oreliminating the accumulation on the surfaces of the blanks of charges ofstatic electricity, whereby the blanks may be delivered from themechanism in a uniform manner.

Another object of the invention is to provide, in a mechanism of thetype referred to, means for regulating the curling action and for aidinthe delivery of the blanks from the terminal or dual curling pass.

Another object of the invention is to provide improved means forsoftening the surface of any coating on the blank to prevent cracking ofthe coating during flattening or reverseiy curling of the blank.

A further object of the invention is to provide a mechanism of the classreferred to that is relatively simple and compact, readily assembled andoperated.

Other objects of the invention will be apparent to those skilled in theart to which our invention relates from the following description takenin connection with the accompanying drawings. wherein Fig. 1 is a frontelevation of a mechanism embodying our invention.

Fi 2 is a section on the line 2-2 of Fig. 1.

Fig. 2a is a fragmentary view of parts shown in Fig. 2, enlarged, andshowing a blank being delivered.

Fig. 3 is a section on the line 3-8 of Fig. 2.

Fig. 4 is a section on the line H of Pig. 2.

In the drawings, l indicates as an entirety a frame preferablycomprising a bottom member 2 and spaced vertical side walls 3, 4. Theseparts may comprise suitable castings. By preference each of the walls 3,4, is provided with inturned lugs 5, which are secured to the base 2 bybolts 6. The central portions of the side walls I, l. are extendedupwardly and support the opposite ends of a plate I, which forms a basefor an electric motor 8, where the blank moving means are to be poweroperated. 9 indicates a suitable switch also mounted on the plate I andcontrolling the supply of current through leads (one being shown at ill)to the motor 8.

I I indicates an endless belt or band formed of resilient, elasticmaterial, such as rubber. B! using a rubber belt, all portions of thebelt maintain substantially the same tension, the belt compensates forslight disalignment of the rolls and unequal stretching throughout itslength. l2, I3, indicateguide rolls for the belt ll, preferably disposedin substantially a horizontal plane, and mounted on the side walls 3, 4,adjacent their front and rear ends, respectively. As later set forth theshaft I3 is driven to drive the belt in the direction of the arrows atas shown in Fig. 2. It indicates an intermediate guide roll for thelower run of the belt mounted at its opposite ends in the side walls 3,l, adjacent their lower horizontal edges, so as to guide the beltdownwardly below and under the curling elements to be later referred to.

The roll I! preferably comprises a hollow element clamp it against thewall 4.

cylinder l2a mounted at its ends on anti-friction bearings l2b, theinner races of the latter being supported on a shaft l2c. The oppositeends of the shaft l2c extend through openings formed in blocks IS. Theblocks l5 slidably fit the lower walls of openings l6 formed in the sidewalls 3, 4, and pins l6a mounted in the upper portion of the openingswhereby the shaft l2c may be adjusted to maintain the belt taut andunder the desired tension. Each block I5 is adjusted by a rotatable rod.I 1 extending through an opening formed in the marginal portion of theadjacent side wall and having bearing at its inner end in the side wallinwardly of the opening l6. The intermediate portion of the screw isthreaded through an opening formed in the block so as to move the latteroutwardly or inwardly when the screw is turned in the proper direction.The outer ends of the rods l1 have heads l1a which engage the ends ofthe side wall and hold the blocks IS in opposition to the tension of thebelt ll. Due to the tension of the belt and engagement of the heads l1awith the side walls, adjustment is effected by rotating the rods l1.

The roll l3 comprises a shaft having reduced ends l3a, l3a', supportedby anti-friction bearings l9 suitably seated in openings 20 formed inthe side walls 3, 4. The reduced and l3a is extended and carries at itsouter end a driving 2|. The driving element is provided with a hub 2l awhich is secured to the shaft end l3a' by a setscrew 22.

. The roll l4 preferably comprises a hollow cylinder l4a mounted at itsends on anti-friction bearings l4b, the inner races of which are supboltbeing reduced and fitting into and through the inner race of thehearing.

The element 2l preferably comprises a pulley driven in the followingmanner: 24 indicates a pulley fixed to the shaft of the motor 8. 26indicates a belt running over the pulley 24 and a pulley 26. 21indicates a pulley preferably formed integrally with the pulley 26. 28indicates a belt running around the pulley 21 and the pulley 2|, wherebythe latter is driven. The

a hub for the pulleys 26, 21, is provided on its inner end with a recessto receive an anti-friction bearing 29, the inner race of which ismounted on a stud shaft 36. The stud shaft 33 is provided with a reducedthreaded inner end which is screwed into a threaded opening 3l formed inthe-adjacent side wall 4 to support the shaft thereon. The intermediateportion of the shaft is reduced to fit into the inner bearing race andto form a shoulder to engage therewith and The outer end of the shaft 36is enlarged to overlap the outer wall of the pulley hub. As will beunderstood from the drawings, the pulleys 24, 26, 21 and 2l havepredetermined ratios to effect the desired reduction "n the speed oftheshaft I3.

32, 33, indicate spaced rolls arranged between the guide rolls l2, l3,and co-operating with the belt II to form a preliminary pass 32' and aterminal or final pass 33' for reversely curling, folding or ilexingeachblank. Each pass is made by feeding or delivering a blank (as later setforth) between the belt ll and adjacent roll so that as the belt movesaround the roll the blank is curled about the axis of the roll. The

l-roll 32 may be constructed and mounted similarly to the roll l4. Theroll 33 may also be constructed and mounted similarly to the roll l4,but to permit its removal in a ready manner, the roll 33 preferablyconsists of a solid cylinder having an outer surface which may be formedof relatively soft rubber 33a, for a purpose later explained. Theopposite ends of the cylinder are reduced, one end being mounted inanti-friction bearings carried by the wall 4 and its opposite end beingmounted in anti-friction bearings provided in a plate 34 which isremovably secured to the outer face of the wall 3 by upper and lowerscrews 34a (only one being shown). By removing the plate 34, the roll 33may be removed endwise through an opening 33 formed in the wall 3. Theroll 33 is removable to permit the substitution of a roll of a differentdiameter to regulate curling. The rubber surface is provided to preventcracking of any surface coating on the blanks. The roll 33 may be solidor provided with a sleeve (as shown) formed of the desired material. Ifdesired, the roll 32 may be mounted similarly to the roll 33.

36 indicates a roll forming a guide for the belt ll and co-operatingwith a guide wall 31 to (a) iron or smooth each blank in the directionof its normal curling tendency prior to its delivery to the preliminarypass and (b) guide each blank to the preliminary pass 32'. The roll 36is preferably constructed and mounted similarly to the rolls l4 and 32and is arranged relatively close to the latter and in the plane of theguide rolls l2 and I3, so that in cooperation with the guide 31 eachblank is carried around a portion of the roll 36 to insure ironing andsmoothing thereof. The roll 36 is spaced from the roll l2 to providebetween it and the roll l2 a horizontal run lie for the belt ll, so thatthe blanks may be laid thereon for feeding to the guide wall 31. Asshown in Fig. 2, the guide wall has an inner portion concentric to theroll 36, but spaced from the belt II to admit the blank between the beltand guide. The guide 31 serves to hold the blank in engagement with thebelt, to smooth the blank as it is carried around the roll 36 and toguide the blank to the pass 32'. The outer portion of the guide 31 isdisposed in spaced parallel relation to the run ll a, its free end beingcurved upwardly to form a throat for each blank.

Each blank is placed on the run lla with its curled up surface opposedto the belt and the latter carries the blank into guiding relation tothe guide 31.

As shown in Fig. 2, the belt I l travels from the roll l2 to the roll36, which guides it to the lower side of the pass roll 32. The guide 31guides the blank around the roll 36 and downwardly, so that it is fed inbetween the belt and roll 32 and around the latter'to make the first orpreliminary pass, the effect of which is to reversely curl or flex theblank without cracking or damaging it or any surface coating thereon.

36 indicates as an entirety means for flexing the blanks oppositely tothe direction of curling or flexing imparted to them by the pass 32 andfor guiding the blanks to the pass 33'. The flexing means 38 comprise arelatively large drum or roll 38' arranged between the passes 32', 33',and over which the belt ll runs from the roll 32 to the roll 33 and astationary guide 39. disposed concentrically to the drum and extendingin spaced relation to the belt substantially throughout that portion ofthe drum engaged by the belt The front end of the guide 39 is preferablyformed integrally with the guide 31, both guides con-- stituting asingle casting fixed to the side walls by screws 33. The rear end of thecasting may be provided with a lug secured to one of the side walls. Therear terminating end of the guide 39 is provided with a rib ll whichprevents the blanks from being carried around with the'roll 33 due tocharges of static electricity thereon.

The drum 38' preferably comprises a hollo sheet metal cylinder 38ahaving neads 38b fitted and secured in its ends in any desired manner.The heads 3317 are formed with axial openings to receive suitableantifriction bearings which are mounted similarly to the bearings forthe rolls I3, 32 and 33. By making the drum relatively large the blanksare conducted or carried from the prelimi nary pass 32' to the terminalor final pass 33' in a simple manner, the arrangement of the guide rollsl2, l3, and pass rolls 36, 32, 33 issimplificd and the lower or returnrun of the belt is provided for by a single guide ro'll l4. Suchconstruction also provides for compactness and relatively small over-alldimensions in height and length of the mechanism.

In operation of the mechanism, each blank is placed on the run Ha, withits curled up face downwardly. From this feeding station the blank iscarried first around the roll 36 and in engagement with the guide 31,which tends to smooth out the blank; next, the blank is carried to andcurled around the roll 32 which gives it a preliminary reverse curl;next, the blank is carried around the drum 38 in engagement with theguide 39, the co-operative relation of which flexes the blank in thedirection of its normal curl or normal curling tendency; next, the blankis carried to and around the roll 33. which gives it a final reversecurl, the blank being discharged by the belt II and allowed to fall intoa receiver 42. From the foregoing description it will be seen that eachblank is given a preliminary reverse curl and a final reverse curl toinsure straightening and permanent set of the blank to enable itshandling, resting or mounting on flat surfaces, mounting or attachmentin albums, wrapping and storing. It will also be seen that in thedisclosed construction, which is the preferred one, the blank isalternately curled or flexed in opposite directions, the eifect of whichis to break down unequal stresses in the fibers, coating on the blank orbetween the coating and blank so that tendency of the blank to curl iseliminated.

It will also be seen that the rolls 36, 32, 33, 33 and I3 areco-operatively arranged to guide the belt one from another, withoutintermediate guides between them, at the same time the belt il makessubstantially a half turn on the rolls 32, 33, to-insure the necessaryreverse curling action on the blanks. This-arrangement serves to reducethe number of parts to a minimum. 33 indicates an auxiliary meansassociated with the roll 33 and belt II, which is shown herein in a formwhereby it is capable of performing three functions, namely,-(1)effecting discharge of static electricity, which due to friction betweenthe blanks and guides or the belt, may accumulate on the blanks and thusprevent their uniform discharge from the final pass or belt ll, (2) ofguiding the blanks from the pass 33' outwardly and (3) regulating orcontrolling the degree of reverse curl as each blank leaves the finalpass 33'.

The auxiliary device 33 preferably comprises a metallic roll 33', havinga length substantially equal to the width of the belt Ii, and removablyresting by its own weight on the roll 33 and adjacent portion of thebelt Ii as it runs around the driven guide rolli3. In this position, theroll 43' contacts with each blank as it leaves the roll 33 andneutralizes or causes the discharge of any electric charge thereon, sothat tendency of the blank to be attracted to adjacent portions of theframe or mechanism is relieved. The position of the roll 43' alsoenables it to direct the blanks outwardly to insure their delivery intothe receiver 42.

While the correlated rolls have a predetermined relation, the resultingcurl imparted to the blanks when passed through the mechanism willdepend upon atmospheric conditions, so that on days having a dryatmosphere the resulting curl of the blanks is greater than on days whenthe atmosphere is damp. To control or regulate the curling of the blanksunder these variable conditions we provide rolls 43' having differentdiameters any one of which may be positioned as shown in Fig. 2 tocompensate for atmospheric conditions. It will be noted that a roll 33'of relatively small diameter will engage the roll 33 and belt I l nearerto the plane cutting the axes of the rolls 33 and I3 than a roll havinga relatively large diameter, so that contact of a roll 43' of largediameter with the blank will be at a greater distance from the point oftangency at which the belt leaves the roll 33 as compared to a roll 43'of smaller diameter. Accordingly, reverse curling effect is reduced byincreasing the diameter of the roll 33, so that by a substitution of theroll 43', varying degrees of reverse curvature may be secured or suchcurvature may be regulated to compensate for atmospheric action.

The mechanism herein disclosed has been successfully used by us forstraightening photographic prints, which have a coating on one surface,but in the use of the term "blank" herein we comprehend sheets, cardsand the like which are coated, devoid oi coatings or which may betreated or conditioned for purposes other than for photographic use. Theside walls 3, 3, may be spaced any desired distance to increase thecapacity of the mechanism. By preference, the several rolls aresupported so that their peripheries may occupy substantially the entirespace between the walls, 3, 3, thereby providing a belt of maximumwidth; also, anti-friction bearings for supporting the pulley hub androlls may be of a type to take end thrusts.

34 indicates a guard disposed below the return run of the belt lladjacent its discharge end. The guard 44 consists of a vertical sheetmetal wall having on its lower edge lateral wings which are secured tothe base 2 by the feet I.

indicates as an entirety means for applying heat to the blanks toprevent cracking of any coating thereon during straightening. Suchheating means have been found to be particularly applicable for use forstraightening blanks, one surface of which has a coating of emulsion,for example photographic prints, and by reason of atmosphericconditions-that is, where the atmosphere is substantially dry-thecoating has become brittle.

Instead of applying water or vapor to the print or either surfacethereof, we have discovered that by apply sa limited amount of heat tothe surface of the emulsion on each blank, such surface may be softenedsufilciently to prevent cracking thereof, as the print makes the passesalready described, without affecting the appearance of the picture orview fixed in the emulsion.

the print through the mechanism. It will thus be seen that the heat isapplied indirectly to the coating of emulsion on each print, whichmethod provides a simplified form of construction since the prints orblanks are delivered to the endless belt and move therewith with theircoated faces thereon.

In the preferred arrangement we mount the heating means 45 above thebottom member 2 and below the return run of the belt ll adjacent thelfl'. receiving end and apply the heat radiating from such means to thebelt Ii. As the belt is driven, all portions thereof become heateduniformly and the belt in turn transmits heat to the rollers 32 and 33,and other parts, so that heat is applied to both surfaces of the blank.In practical operation of machines of the construction shown in theaccompanying drawings,- the application of the heat to the coated blankas just described has no effect upon the appearance of the picture inthe coat on the blank and insures straightening thereof without dangerof cracking of the coating. The heating means preferably comprises anelectrical heating unit, such as a lamp bulb 48, which may have a carbonfilament. The plug 3 0f the bulb 45 is mounted in a socket 41, which issecured to a nipple 48 threaded through the wall 3. The leads for thelamp bulb are connected to the lead cable I0, so that the switch 9 willsupply current to it and the motor. The

85 ;-bil1b is independently controlled by the switch key 49. The socket41 supports a collar 50 having a reflector ii to direct the radiant heattoward the belt. The heating means may be applied to the entire belt IIby a plurality of heating ele- 'ments or a single element, but inpractical use we have found that a single unit disposed substantiallycentrally and extending transversely across a large area of the beltwill provide ample heat to soften the surface of the emulsion on eachprint without changing, altering or affecting the view fixed therein.

By applying the heat to a material which is non-hygroscopic and capableof absorbing heat units, and moving such material past the heat source,the heat is uniformly distributed therein.

As all heat absorbed by the rolls is derived by contact with the belt,it will be seen that there is but slight difference in temperature, ifany, between any of the parts. The collar 50 is removable from .thesocket 41 and it is also rotatable thereon to permit of adjustment ofthe deflector 5|.

To those skilled in the art to which our invention relates, many changesin construction and widely differing embodiments and applications oi theinvention will suggest themselves without departing from the spirit andscope of the invention. Our disclosures and the description herein arepurely illustrative and not intended to be in any sense limiting.

05 What we claim is:

1. In a machine for straightening blanks provided with a coated surface,the combination of a plurality of spaced passes arranged to curl blanksin the same direction, said passes comprising pairs of related rolls andan endless belt engaging therewith, and means between said passes forflexing the blanks in the opposite direction, said means comprising arelatively large roll over which said belt travels and a stationaryguide extending concentrically to said belt.

2. In mechanism for straightening blanks provided with a coated surface,the combination of an endless belt, front and rear guide rolls for saidbelt, spaced rolls arranged between said guide rolls and around whichsaid belt runs and respectively co-operating with said guide rolls togive blanks a preliminary curl and a final curl in the same direction,means for guiding the belt and blank to each said curling roll, andmeans associated with the final curling roll and adjacent guide roll forengaging each blank as it is delivered from said curling roll formodifying the curl imparted to the blanks by said final curling roll.

3. In mechanism for straightening blanks provided with a coated surface,the combination of an endless belt, front and rear guide rolls for saidbelt, spaced rolls arranged between said guide rolls and around whichsaid belt runs and respectively co-operating with said guide rolls togive blanks a preliminary curl and a final curl in the same direction,means for guiding the belt and blank to each said curling roll, and achangeable device removably engaging with the final curling roll andbelt as it is guided to the adjacent guide roll and arranged to engageeach blank as it is delivered from said curling roll for modifying the Icurl imparted to the blanks by said final curling roll.

4. In mechanism for straightening blanks provided with a coated surface,the combination of an endless belt, front and rear guide rolls for saidbelt, spaced rolls arranged between said guide rolls and around whichsaid belt runs and respectively co-operating with said guide rolls togive blanks a preliminary curl and a final curl in the same direction,means for guiding the belt and blank to each said curling roll, and ametallic roll resting on the final curling roll and belt as it is guidedto the adjacent guide roll and rotated by said curling roll and belt andarranged to engage each blank as it is delivered from said curling rollfor dissipating electrical charges generated on the blanks duringcurling thereof.

5. In mechanism for straightening blanks provided with a coated surface,the combination of spaced pairs of co-operating rolls and an endlessbelt engaging therewith and adapted to convey blanks successively tosaid pairs of rolls to curl them reversely to their normal curlingtendcncy and to discharge them from the last pair of rolls, and meansassociated with the last pair of rolls for neutralizing electric chargeson the blanks.

6. In a machine for straightening blanks provided with a coated surface,the combination of front and rear guide rolls disposed in spacedrelation, a co-operating roll disposed adjacent each of said guiderolls, related guide devices between the last mentioned rolls, anendless belt engaging said front guide roll, the adjacent co-operatingroll, one of said guide devices, the other cooperating roll and saidrear guide roll and arranged to convey the blanks first around saidcooperating roll adjacent said front guide roll, then relative to saidguide devices and finally around the other co-operating roll, and meansfor driving said belt, said co-operating rolls and belt serving to curlthe blanks reversely to their normal curling tendency. f

"I. In a machine for straightening blanks provided with a coatedsurface, the combination of front and rear guide rolls disposed inspaced relation, a co-operating roll disposed adjacent each of saidguide rolls, related guide devices between the last mentioned rolls, anendless belt engaging said front guide roll, the adjacent co-operatingroll, one of said guide devices, the other co-operating roll and saidrear guide roll, and arranged to convey the blanks first around theco-operating roll adjacent said front guide, then relative to said guidedevices and finally around the other co-operating roll, means fordriving said belt, and a roll engaging the last referred to cooperatingroll and adjacent portion of the belt and arranged to engage said blankas it disengages said co-operating roll.

8. In a machine for straightening blanks provided with a coated surface,the combinationof front and rear guide rolls disposed in spacedrelation, a co-operating roll disposed adjacent each of said guiderolls, related guide devices between the last mentioned rolls, anendless belt engaging said iront guide roll, the adjacent cooperatingroll, one of said guide devices, the other co-operating roll and saidrear guide roll and arranged to convey the blanks first around saidco-operating roll adjacent said front guide roll, then relative to saidguide devices and finally around the other co-operating roll, saidco-operating rolls and belt serving to curl the blanks reverseLv totheir normal curling tendency, means for driving said belt, and meansco-operating with the rear guide roll and the adjacent co-operating rollfor regulating the curl of the blanks effected by said co-operatingroll.

9. In a machine for straightening blanks provided with a coated surface,the combination of front and rear guide rolls disposed in spacedrelation, a co-operating roll disposed adjacent each of said guiderolls, related guide devices between the last mentioned rolls, anendless belt engaging said front guide roll, the adjacent co-operatingroll, one of said guide devices, the other co-operating roll and saidrear guide roll and arranged to convey the blanks first around saidco-operating roll adjacent said front guide roll, then relative to saidguide devices and finally around the other co-operating roll, saidco-operating rolls and belt serving to curl the blanks reversely totheir normal curling tendency, means for driving said belt, and meansoperating without impregnating the blanks or the coat thereon withmoisture to prevent cracking of the coated surface on each blank as itis conveyed by said belt.

10. In a machine for straightening blanks provided with a coatedsurface. the combination of front and rear guide rolls disposed inspaced relation, a co-operating roll disposed adjacent each of saidguide rolls, related guide devices between the last mentioned rolls, anendless belt engaging said front guide roll. the adjacent cooperatingroll, one of said guide devices, the other co-operating roll and saidrear guide roll and arranged to convey the blanks first around saidco-o'perating roll adjacent said front guide roll, then relative to saidguide devices and finally around the other co-operating roll, saidco-operating rolls and belt serving to curl the blanks reversely totheir normal curling tendency, means for driving said belt, and meansfor preventing cracking of the coated surface on each blank as it isconveyed by said belt, the last said means comprising a source of heatsupply arranged to heat said belt while being driven.

11. In a machine for straightening blanks provided with a coatedsurface, the combination of frontandrearguideroilsdisposedinspacedrelation, a co-operating roll disposed adjacent each of said guiderolls, related guide devices between the last mentioned rolls, anendless belt engaging said front guide roll, the adjacent cooperatingroll, one of said guide devices, the other co-operating roll and saidrear guide roll and arranged to convey the blanks first around saidco-operating roll adjacent said front guide roll, then relative to saidguide devices and finally around the other co-operating roll, and meansfor driving said belt, said co-operating rolls and belt serving to curlthe blanks reversely to their normal curling tendency and said relatedguide devices comprising spaced, concentricalLv disposed curvilinearwalls arranged to curl the blanks in a direction opposite to the curlingeffected by the (So-operating rolls.

12. In a machine for straightening blanks provided with a coatedsurface, the combination of front and rear guide rolls disposed inspaced relation, a co-operating roll disposed adjacent each of saidguide rolls, related guide devices between the last mentioned rolls, anendless belt engaging said front guide roll, the adjacent co-operatingroll, one of said guide devices, the other cooperating roll and saidrear guide roll and arranged to convey the blanks first around saidco-operating roll adjacent said front guide roll, then relative to saidguide devices and finally around the other co-operating roll, and meansfor driving said belt, said co-operating rolls and belt serving to curlthe blanks reversely to their normal curling tendency, said relatedguide devices consisting of a drum around which the belt travels and astationary, curvilinear wall disposed concentrically to the periphery ofsaid drum, said drum and wall co-operating, as the blanks are conveyedby said belt, to curl them in a direction opposite to the curlingeffected by said co-operating rolls.

13. In a machine for straightening blanks provided with a coatedsurface, the combination of front and rear guide rolls disposed inspaced relation, a co-operating roll disposed adjacent each of saidguide rolls, related guide devices between the last mentioned rolls, anendless belt engaging said front guide roll, the adjacent co-operatingroll, one of said guide devices, the other co-operating roll and saidrear guide roll and arranged to convey the blanks first around saidco-operating roll adjacent said front guide roll, then relative to saidguide devices and finally around the other co-operating roll, and meansfor driving said belt, said co-operating rolls and belt serving to curlthe blanks reversely to their normal curling tendency, said relatedguide devices comprising spaced, concentrically disposed curvilinearwalls struck on radii greater than the radii of said co-operating rollsand arranged to curl the blanks in a direction opposite to the directionof curling effected by said co-operating rolls. a

14. In a machine for straightening blanks provided with a coatedsurface, the combination of front and rear guide mils disposed in spacedrelation, a co-operating roll disposed adjacent each of said guiderolls, related guide devices between the last mentioned rolls, anendless belt formed of elastic non-hygroscopic material engaging saidfront guide roll, the adjacent co-operating roll, one of said guidedevices, the other co -operating roll and said rear guide roll andarranged to convey the blanks first around said co-operating rolladjacent said front guide roll, then relative to said guide devices andfinally around the other co-operating roll, and means for driving saidbelt, said co-operating rolls and bull, serving to curl the blanksreversely to their normal curling tendency.

15. In a machine for straighten blanks provided with a coated surfacethe combination of front and rear guide rolls disposed in spacedrelation, 2. co-operating roll disposed adjacent each of said guiderolls, related guide devices between the last mentioned rolls, anendless belt formed of elastic, non-hydroscopic material engaging saidfront guide roll, the adjacent cooperating roll, one of said guidedevices, the other co-operating roll and said rear guide roll andarranged to convey the blanks first around said co-operating rolladjacent said front guide roll, then relative to said guide devices andfinally around the other co-operating roll, means for applying heat tothe belt, and means for driving said belt, said co-operatlng rolls andbelt serving to curl the blanks reversely to their normal curlingtendency.

ELMER. H. BRUNNER.

SAMUEL A. WALL.

